Household appliance

ABSTRACT

A household appliance has a container for receiving working material and a housing that is isolated from the container by a wall. A rotatable working tool disposed inside the container. A motor for driving the working tool has a stator and a rotor. The stator is disposed within the housing so as to be isolated from the working material of the container. The rotor is disposed within the container and the working tool is preferably fixed to a shaft of the rotor.

CROSS REFERENCE TO RELATED APPLICATIONS

This non-provisional patent application claims priority under 35 U.S.C.§119(a) from Patent Application No. 201010183840.8 filed in The People'sRepublic of China on May 20, 2010.

STATOR OF THE INVENTION

The present invention relates to household appliances and in particularto kitchen appliances such as soy milk makers, juice extractors, mixers,egg beaters, etc.

BACKGROUND OF THE INVENTION

As shown in FIG. 9, a known soy milk maker comprises an upper closedhousing 11, a lower cup shaped housing 12 supporting the upper housing11, and a motor 13 disposed inside the upper housing 11. The motor 13comprises a rotor shaft 14 that extends into the lower housing 12.Blades 15 are fixed to the shaft 14 and rotate with the shaft 14. Theupper housing 11 is detachable from the lower housing 12 for cleaningthe blades 15. The bottom of the upper housing 11 comprises a sealstructure 16 to avoid the motor 13 being affected by moisture from thelower housing 12.

However, the seal structure 16 affects the motor output. Also, the sealstructure 16 will become worn over the time and the motor 13 will becomeaffected by moisture.

SUMMARY OF THE INVENTION

Accordingly, in one aspect thereof, the present invention provides ahousehold appliance comprising: a container for receiving liquidcontaining material; a housing that is isolated from the container by awall; a rotatable working tool disposed inside the container; and amotor for driving the working tool, comprising a stator and a rotor;wherein the stator comprises stator windings disposed within the housingand the rotor comprises a rotor shaft and a rotor magnet fixed to therotor shaft disposed within the container, the stator windings and therotor magnet being separated by the wall and the rotor shaft does notpass through the wall.

Preferably, a support member is disposed inside the container and fixedto the housing, the rotor shaft being rotatably supported by the supportmember via a bearing.

Preferably, the rotor magnet and the stator windings are axiallyconfronting, the stator windings comprising disc windings fixed to astator core and the rotor magnet comprises a disc magnet disposed at oneside of a magnetically conductive member adjacent the stator windings.

Preferably, the rotor magnet and the magnetically conductive member arerotatable supported by a fixed shaft, and the rotor shaft being fixedwith the rotor magnet and the magnetically conductive member.

Alternatively, rotor magnet and the stator windings are radiallyconfronting.

Preferably, the rotor magnet comprises a cylindrical magnet fixed to therotor shaft, and the wall comprises a recess for receiving the rotormagnet, the stator windings being disposed inside the housing and aroundthe recess to confront the rotor magnet.

Preferably, the wall comprises a projection that extends outwardly fromthe housing and the stator windings are disposed inside the projection,and the rotor magnet comprises a ring magnet disposed around theprojection and confronting the stator windings.

Preferably, the stator is disposed above the container.

Alternatively, the stator is disposed below the container.

Preferably, a hood is disposed inside the container and mounted to thehousing, the rotor and the working tool being disposed inside the hood,the interior of the hood communicating with the interior of thecontainer.

Preferably, the rotor magnet comprises a number of discrete permanentmagnet pieces.

Preferably, the household appliance is a soy milk maker, grain grinder,juice extractor, mixer or egg beater.

By implementing the invention, the stator and other electric componentare isolated from the container where the liquid or liquid containingmaterial is disposed. Therefore, the stator and the components are notaffected by moisture from the container.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way ofexample only, with reference to figures of the accompanying drawings. Inthe figures, identical structures, elements or parts that appear in morethan one figure are generally labeled with a same reference numeral inall the figures in which they appear. Dimensions of components andfeatures shown in the figures are generally chosen for convenience andclarity of presentation and are not necessarily shown to scale. Thefigures are listed below.

FIG. 1 schematically illustrates a household appliance according to afirst embodiment of the present invention;

FIG. 2 schematically illustrates stator windings of a motor of thehousehold appliance of FIG. 1;

FIG. 3 schematically illustrates a rotor of the motor of the householdappliance of FIG. 1;

FIG. 4 illustrates a support member of the household appliance of FIG.1;

FIG. 5 illustrates an alternative support member;

FIG. 6 schematically illustrates another household appliance accordingto a second embodiment of the present invention;

FIG. 7 schematically illustrates another household appliance accordingto a third embodiment of the present invention;

FIG. 8 schematically illustrates a further household appliance accordingto a fourth embodiment of the present invention; and

FIG. 9 schematically illustrates a known household appliance in the formof a soy milk maker.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described with reference to various householdappliances in the form of a soy milk maker, by way of example. Thehousehold appliance of the first embodiment, as shown in FIGS. 1 to 3,comprises a container 20 for receiving liquid or liquid containingmaterial such as fruits, a rotatable working tool 30 disposed inside thecontainer 20, and a motor for driving the working tool 30.

The motor comprises a stator 40 and a rotor 50. The stator 40 is mountedoutside the container 20 and is isolated from the container 20.Preferably, the stator 40 is disposed inside a closed housing 70 that isdisposed above the container 20. The stator 40 comprises stator windings42 that are formed as a disc by over molding or other means. The statorwindings 42 are fixed to a stator core 44. The motor further comprisesother electric components such as a control module 46 to control thecurrent flow of the stator windings 42 and/or other electric components,which may be accommodated in the housing 70 so as to be isolated fromthe liquid of the container 20.

The rotor 50 is received in the container 20. The rotor 50 comprisesrotor magnets 52 and a magnetic conductive member 54 that is disposed atone side of the rotor magnets 52 remote from the stator. The rotormagnets 52 and the magnetic conductive member 54 form a magnetic body ofthe rotor 50. Preferably, the magnetic body is disc shaped. The rotormagnets 52 are disposed adjacent but axially spaced from the statorwindings 42. In this embodiment, the stator windings 42 and the rotormagnets 52 are separated by the bottom of the housing 70. There is a gapbetween the bottom and the rotor magnets 52 to allow the rotor magnetsto rotate. The rotor magnets 52 are axially magnetized. Preferably, fourpoles are formed in the rotor magnets 52. The magnetic flux path isformed by the magnetic conductive member 54, the rotor magnets 52, thegap between the bottom of the housing 70 and the rotor magnets 52, thestator windings 42 and the stator core 44. When the stator windings 42are energized, the rotor 50 is driven by the stator 40. The stator 40may comprise one or more sensors for sensing the rotation of the rotor50. Depending on the controller, a sensor may not be required or may bereplaced by other means.

The rotor 50 comprises a rotor shaft 56 on which the working tool 30 isfixed. The rotor magnets 52 and the conductive member 54 are also fixedto the shaft 56. The shaft 56 is rotatably supported by a bearing 58that is mounted to a support member 59. Preferably, the bearing 58 is awater proof bearing. In this embodiment, there is a hood 60 inside thecontainer 20. The hood 60 is mounted to the top of container 20 or thebottom of the housing 70. The rotor magnets 52, the magnetic conductivemember 54, the rotor shaft 56, the support member 59 and the workingtool 30 are inside the hood 60. Through holes are formed in the hood 60so that the interior of the hood 60 is communicated with the interior ofthe container 20. The hood 60 provides a screen to filter out largeparticles, such as pieces of the soy beans been ground to form soy milk.The hood 60 also provides a structure for the fixing of the supportmember 59.

FIG. 4, illustrates the support member 59 which comprises a center ringmember 592 and a plurality of radial ribs 594 extending outwardly fromthe ring member 592. A mounting hole 598 is formed in the ring member592 for holding the bearing 58. Water or brushes can pass through theopenings 596 formed between the ribs 594 for cleaning the rotor magnets52 and the magnetic conductive member 54.

The hood 60 is not essential. For instance, FIG. 5 illustrates amodified support member 59 in the form of a cage which could bedetachably mounted to the bottom of the housing 70. The cage shapedsupport member 50 also comprises a plurality of openings 596 for wateror brushes to pass through.

In the above embodiment, the container 20 is below the housing 70.Alternatively, the container 20 could be disposed above the housing 70.

In the embodiment of FIG. 6, the container 20 is disposed above andsupported by the housing 70. The magnets 52 and the magnetic conductivemember 54 are rotatably supported by a fixed shaft 57 via a bearing 58.The fixed shaft 57 is fixed to the housing 70 or the bottom of thecontainer 20. The rotor shaft 56 is fixed to the magnets 52 and magneticconductive member 54. The rotor shaft 56 of FIG. 6 is much shorter thanthe shaft of FIG. 1.

In the third embodiment of FIG. 7, the rotor magnet 52 is a cylindricalmagnet fixed to rotor shaft 56. The rotor magnet 52 is magnetizedradially. The stator comprises a recess 72 for receiving the rotormagnet 52. The stator windings 42 are in ring form and disposedconfronting the cylindrical magnet 52. The stator is disposed within theclosed housing 70. The housing 70 is disposed above the container 20.Alternatively, the housing 70 may be disposed below the container 20 andsupports the container 20.

In the fourth embodiment shown in FIG. 8, the rotor magnet 52 is a ringmagnet. The housing 70 has a projection that extends out of the bottomof the closed housing 70 and received inside the ring magnet. The statorwindings 42 and stator core are disposed inside the projection. Therotor magnet 52 is radially magnetized. A flux ring or magnetic housingcould be disposed about the magnet and used to fix the magnet to theshaft. The closed housing 70 could be disposed below the container 20.

In the embodiments described above, the rotor is disposed in a firstchamber formed by the container 20. The stator winding 42, stator core44 and other electric components are disposed in a second chamber formedby the housing 70. The second chamber is isolated from the first chamberby a wall to avoid the stator 40 and the electric components 46 beingaffected by moisture from the first chamber. For instance, the wall isformed by the bottom of the housing 70. The rotor shaft 56 does not passthrough the wall. The rotor could be made by water proof material, orhave water proof coating. Further more, the liquid or liquid containingfood inside the container 20 could be magnetized by the rotor magnetsince the rotor magnet 52 is disposed inside the first chamber formed bythe container 20.

The household appliance illustrated is a soy milk maker and the workingtool is a number of blades fixed to the rotor shaft. Alternatively, thehousehold appliance could be a juicer extractor, grain grinder, mixer oreggbeater, etc.

In the description and claims of the present application, each of theverbs “comprise”, “include”, “contain” and “have”, and variationsthereof, are used in an inclusive sense, to specify the presence of thestated item but not to exclude the presence of additional items.

Although the invention is described with reference to one or morepreferred embodiments, it should be appreciated by those skilled in theart that various modifications are possible. Therefore, the scope of theinvention is to be determined by reference to the claims that follow.

For example, while the rotor magnet has been illustrated as a singlepiece permanent magnet, it could be formed by a number of discretepermanent magnet pieces.

1. A household appliance comprising: a container for receiving liquidcontaining material; a housing that is isolated from the container by awall; a rotatable working tool disposed inside the container; and amotor for driving the working tool, comprising a stator and a rotor;wherein the stator comprises stator windings disposed within the housingand the rotor comprises a rotor shaft and a rotor magnet fixed to therotor shaft disposed within the container, the stator windings and therotor magnet being separated by the wall and the rotor shaft does notpass through the wall.
 2. The household appliance of claim 1, furthercomprising a support member disposed inside the container and fixed tothe housing, the rotor shaft being rotatably supported by the supportmember via a bearing.
 3. The household appliance of claim 1, wherein therotor magnet and the stator windings are axially confronting, the statorwindings comprising disc windings fixed to a stator core and the rotormagnet comprises a disc magnet disposed at one side of a magneticallyconductive member adjacent the stator windings.
 4. The householdappliance of claim 3, wherein the rotor magnet and the magneticallyconductive member are rotatable supported by a fixed shaft, and therotor shaft being fixed with the rotor magnet and the magneticallyconductive member.
 5. The household appliance of claim 1, wherein rotormagnet and the stator windings are radially confronting.
 6. Thehousehold appliance of claim 5, wherein the rotor magnet comprises acylindrical magnet fixed to the rotor shaft, and the wall comprises arecess for receiving the rotor magnet, the stator windings beingdisposed inside the housing and around the recess to confront the rotormagnet.
 7. The household appliance of claim 5, wherein the wallcomprises a projection that extends outwardly from the housing and thestator windings are disposed inside the projection, and the rotor magnetcomprises a ring magnet disposed around the projection and confrontingthe stator windings.
 8. The household appliance of claim 1, wherein thestator is disposed above the container.
 9. The household appliance ofclaim 1, wherein the stator is disposed below the container.
 10. Thehousehold appliance of claim 1, further comprising a hood disposedinside the container and mounted to the housing, the rotor and theworking tool being disposed inside the hood, the interior of the hoodcommunicating with the interior of the container.
 11. The householdappliance of claim 1, wherein the rotor magnet comprises a number ofdiscrete permanent magnet pieces.
 12. The household appliance of claim1, wherein the household appliance is a soy milk maker, grain grinder,juice extractor, mixer or egg beater.